1. Field
This invention relates generally to clock signal distribution. More specifically, this invention relates to a system and method for spatial clock signal distribution using an electronic package.
2. General Background and Related Art
In microelectronic chips such as microprocessors, the operations of multiple chip components must be synchronized. Yet, the physical separation of such components may cause significant propagation delay-induced phase shifts. In recent years, the operating frequency, or clock frequency, of microprocessors has steadily risen. Because of such increases in clock frequency, as well as increased system function, problems relating to high-frequency effects and power consumption have become more pronounced. As such, clock distribution techniques have been proposed to minimize these effects.
A number of clock distribution techniques have involved propagating clock signals in order to synchronize the signals at receiving points. For example, clock signals are generated on-chip using microchip transmission lines 10 arranged on a microelectronic chip in a so-called H-tree, as shown in FIG. 1 (Prior Art). The purpose of the H-tree structure is to minimize skew due to different path lengths from a clock generator 20 to the various receiving elements. Propagation loss and repeated branching at T-junctions 30 generally require the introduction to a microelectronic chip of clock buffers 40 that receive and retransmit a clock signal along a path from the clock generator 20 to any particular clock receiver 50. In some systems that include H-tree structures, a clock signal could traverse, for example, as many as ten stages of clock buffers before reaching its final destination. Because of the large number of such elements, skew, jitter, and excessive power consumption result.
Standing-wave behavior is characterized by discontinuous progression or abrupt jumps in the advancement of phase with distance. This behavior is a fundamental property of standing waves in any physical situation governed by the wave equation and where the signal is isophasic, that is, its phase remains constant over extended regions and abruptly jumps by 180xc2x0 between adjacent regions. A clock distribution technique has attempted to exploit the spatial phase characteristics of a standing wave to minimize clock skew. In particular, standing waves are generated on a semiconductor die and extended to clock receivers at various entities to be synchronized. However, amplifiers and phase advancing units must be employed along transmission paths to minimize losses.
Therefore, what is needed is an improved system and method for distributing a clock signal.